This invention relates to a method for artificially reducing the strength of the nearbottom offshore directed current inside the surfzone thereby promoting sand accretion on the beach.
Beach erosion is a significant problem throughout the industrialized world. Although there can be a variety of causes, beach erosion can often be traced back to the construction of dams and flood control structures which cut off the natural supply of sand to the beach. This results in a gradual reduction of beach width, first manifesting itself near the mouth of the affected river or stream, and slowly spreading down coast. Eventually beaches become so narrow that winter storm waves begin to directly threaten beachfront structures.
Traditional beach erosion solutions have included seawalls, groin fields, offshore breakwaters and artificial beach nourishment. With the exception of seawalls, these solutions act to widen the beach, either by increasing the sand supply (beach nourishment), or slowing the rate of longshore sand transport (groins and offshore breakwaters). Seawalls simply shield the shoreward property from wave action, while doing nothing to address the ongoing beach erosion problem. In addition, all of these approaches are expensive and time consuming to construct.
The present invention seeks to limit beach erosion by altering the nearbottom velocity field within the surfzone thereby promoting onshore sand transport and widening the beach.